Adaptation to chronic acidic extracellular pH elicits a sustained increase in lung cancer cell invasion and metastasis.

Acidic extracellular pH (pH) is an important microenvironment for cancer cells. This study assessed whether adaptation to acidic pH enhances the metastatic phenotype of tumor cells. The low metastatic variant of Lewis lung carcinoma (LLCm1) cells were subjected to stepwise acidification, establishing acidic pH-adapted (LLCm1A) cells growing exponentially at pH 6.